I would try and find out the amount of feed is he is consuming daily, he should be eating around 25 pounds a day. I would also get him off the heifer feed and on to a steer ration, it sounds like you are feeding a custom mix for heifers, he may need more fat and less protein in his diet.
If you are getting the feed from a mill ask them what they suggest, if your feeding sack feed, find a grower or steer ration to feed. You might add some Stabilized rice bran to his feed as well it will help with the fat content of the feed and not burn him up (2 pounds a day)
Here is the ration we fed
CHAMPIONS CHOICE CALF RATION
Improved feed efficiency; for reduction of incidence of liver abscesses caused by Fusobacterium necrophorum and Arcanobacterium (Actinomyces) pyogenes.
ACTIVE DRUG INGREDIENTS
Monensin ................................ 30 g/ton
Tylosin .................................... 10 g/ton
LIMITATIONS
Feed only to cattle being fed in confinement for slaughter. Feed continuously at the rate of 8.2 to 10.2 kilograms (18 to 22.5 pounds) of Type C medicated feed per head per day to supply 240 milligrams of monensin and 90 milligrams of tylosin per head per day; as monensin sodium; as tylosin phosphate. Safe use in unapproved species and breeding cattle has not been established.
CAUTION
Do not allow horses or other equines access to formulations containing Monensin. Inadequate mixing or agitation of monensin liquid type B medicated feed has resulted in increased monensin concentration, which has been fatal to cattle. Ingestion of Monensin by equines has been fatal. Feeding undiluted or mixing errors resulting in high concentrations of Monensin could be fatal to cattle. Must be thoroughly mixed in feeds before use; do not feed undiluted.
CAUTION
This feed contains a source of non-protein nitrogen. Provide adequate drinking water and do not use with other feed containing non-protein nitrogen. Caution should be exercised with, starved, stressed or debilitated animals. All manufacturer's directions for use must be followed carefully. FOR RUMINATES ONLY
WARNING: EXCESSIVE CONSUMPTION MAY RESULT IN ADVERSE TOXIC REACTION - USE ONLY AS DIRECTED
USE LEVEL
Feed only to cattle being fed in confinement for slaughter. Feed continuously at a rate of 8-10 g/ton Tylosin and 5-30 g/ton of Monensin to provide 90 mg of Tylosin and 50 to 360 mg Monensin per head per day.
Feed Grain concentrate at 2-3% of body weight along with roughage. Provide free choice, salt and fresh, clean water at all times.
Guaranteed Analysis
CRUDE PROTEIN(Min) 11.0%
* (INCLUDES NOT MORE THAN 1.5 % EQUIVALENT CRUDE PROTEIN FROM NON-PROTEIN NITROGEN)
CRUDE FAT (Min) 4.5%
CRUDE FIBER (Max) 12.3%
ASH (Max) 7.5%
List of Ingredients
Corn cracked, Cottonseed Hulls (Not more than 22.8%), Recleaned oats (fancy), Rolled Barley, Soybean Meal, Molasses, Vegetable liquid Fat, Wheat Millrun, Calcium Carbonate, Dicalcium Phosphate, Corn Distillers, Linseed Meal Expeller, Urea, Sodium Silico Aluminate, Vegetable Oil, Salt, Sodium Sesquicarbonate, Whey Dried, Vitamin A Supplement, Vitamin D3 Supplement, Vitamin E supplement, Brewers Dried Yeast, Dried Saccharomyces cerevisiae fermentation solubles, Brewers Yeast Dehydrated, Kelp (Seaweed Meal), Zinc Methionine, Manganese Methionine, Copper Lysine, Cobalt Glucoheptoate, Anise flavor dry, Magnesium Oxide, Monensin, Tylosin Phosphate, Sulfur, Selenium Yeast, Brewers Dried Yeast, Saccharomyces cerevisiae yeast, Cane Molasses, Diastatic Malt, Corn Syrup, Propionic Acid, Ammonium Hydroxide, Verxite, Bentonite, Artificial flavoring, Manganese Sulfate, Zinc Sulfate, Copper Sulfate, Ferrous Sulfate, Niacin, Riboflavin Supplement, Calcium Pantothenate, Biotin, Choline Chloride, Sodium Selenite, Thiamine Mononitrate, Vitamin B-12 Supplement, Folic Acid, Calcium Iodate, Rice Bran, Cobalt sulfate.
50# 500985 MEDICATED